Systems and methods to harvest energy and determine water holdup using the magnetohydrodynamic principle

ABSTRACT

Embodiments provide systems and methods for creating and storing energy using the magnetohydrodynamic principle and the flow of a conductive fluid through a magnetic field downhole in a pipeline system. The system can also be configured to determine water holdup using the magnetohydrodynamic principle. The energy the system generates can be used to control electric valves and other electronic devices along the pipeline. The power storing and generating system can be configured to include permanent magnets, electrode pairs, isolation material, and a conductive flowing multiphase media. The multiphase media, i.e., oil, gas, water, or a mixture, flows through a pipeline that has electrodes in direct contact with the media and magnets also configured adjacent the media. The electrode pairs can be arranged inside of the pipeline opposite each other, with a permanent magnet placed between the electrodes and flush to the inside of the pipe, with flux lines perpendicular to the flow direction. Power output from the system is a function of the conductive fluid volume, flow velocity, magnet strength, and electrode size. Various embodiments include different arrangements of permanent magnets and electrode pairs.

PRIORITY

This application is a continuation of and claims priority to U.S. patentapplication Ser. No. 15/634,014, filed Jun. 27, 2017 titled SYSTEMS ANDMETHODS TO HARVEST ENERGY AND DETERMINE WATER HOLDUP USING THEMAGNETOHYDRODYNAMIC PRINCIPLE and the entire disclosure of which isincorporated here by reference.

BACKGROUND

Embodiments of the present disclosure relate to systems and methods forgenerating electrical power using the magnetohydrodynamic (“MHD”)principle. More particularly, embodiments relate to utilizing multiphaseflow to determine water holdup and to create and store energy to powerdownhole equipment in a pipeline system.

Description of Related Art

The oil and gas industry has a fairly large need for electrical power inall areas of its business, including wells, pipelines, and refineries.Various equipment used in the oil and gas industry, such as valves andsensors require power to function. This power can be supplied by a powergrid or other means. However, it is also desirable to power thesedevices through the use of power generated on site. Further, forefficiency reasons, powering these devices through wires is notdesirable given the fact that remote power locations can be costly tooperate. Given the length of pipeline systems, wires are likely to bedamaged. These replacement costs are high and therefore another sourceof power that is sustainable is necessary.

In view of the above problems, the following new methods and systemsseek to generate and provide power to equipment in a pipeline system onsite. Providing power at the wellsite underground and in hard to reachareas helps to reduce the cost of replacing downed wires and remotepower systems. Water holdup determinations based on the energy generatedover a particular period of time for a particular reservoir is alsoachievable by some of the described embodiments.

SUMMARY

Embodiments of the present application are directed to a system andmethod for generating and storing power using the MHD principle in apipeline system. The MHD principle deals with current flow induced in anelectrically conductive material when it is placed in a magnetic field.The MHD system, according to various embodiments, is attached to aportion of a pipeline where it harvests energy generated from a flowingmedia through the pipe portion and uses the energy to power otherequipment on the pipeline. For instance, the generated and stored poweris used to provide electric power to valves and other electronicequipment that may be configured downhole. When a conductive fluid flowsthrough a permanent magnetic field, it generates kinetic energy that canbe converted into electricity by separating charged particles. Thisgenerates an electric field traverse to the direction of fluid flow andmagnetic field. The electric field generated can be used to powerlow-energy demanding valves and gauges downhole in a producer orinjector or other electronic equipment that may be configured downhole.

The system uses permanent magnets, so that the magnetic field isconstant and therefore the variation in power generated is a function ofthe volume of conductive fluid and flow velocity. Thenaturally-occurring saline water with high conductivity within the gas,oil, and water flow of the pipeline system is the source of the powergeneration in the invention. The device can also be configured tomeasure water holdup based on the amount of power generated in either adownhole application or for surface pipes. Leads are attached to eachelectrode to bring the power to the valves and other electronicequipment downhole. In an embodiment, the valves or other electronicequipment downhole can be configured with a smart power system withcapacitance to store the energy being generated by the system. Inanother embodiment, batteries may also be configured to store the energybeing generated. Such a valve or downhole electronics setup can furtherbe configured, in an embodiment, to receive wireless control andconfiguration signals and messages from a control room or control systemthat direct the operation of the valve or other electronic equipment.The valve and other electronic equipment may also be configured toreceive control and configuration communications via wireless or viawired communication channels.

Embodiments of systems and methods of the present disclosure aredesigned, for example, to safely, accurately, and reliably generate andstore energy that can be provided to various devices attached to thepipeline, such as electrically-actuated or electronically-controlledvalves downhole in a producer or injector.

Embodiments of systems and methods of the present disclosure generateand store power by having a conductive fluid flow through a permanentmagnetic field. The system converts the kinetic energy of the conductivefluid into electricity by separating the charged particles using magnetsand electrodes, which generate an electric field transverse to thedirection of fluid flow and magnetic field.

Embodiments of systems and methods of the present disclosure calculatethe power generated based on the amount and speed of the conductivefluid flow through the system. When the magnetic field is kept constant,the velocity and volume of conductive fluid (i.e., formation water) willimpact the amount of power generated. This effect can be used todetermine the conductive fluid holdup, which relates to the velocity ofthe fluid and the conductive fluid cut. Flow patterns for variousReynolds numbers can be captured by the design of the system.

Embodiments of systems and methods of the present disclosure include apower harvesting MHD system consisting of permanent magnets, electrodes,isolation material, and a conductive flowing material, among otherpieces of equipment. The system can be configured to include acombination of the previously listed components and various magnets andelectrodes of various types, length, size, locations, and orientationsfor both surface pipelines, downhole systems, and for injectors andproducers.

According to an embodiment, there is provided a MHD power generationsystem configured in a pipeline with one or more permanent magnets, oneor more flow tubes arranged inside the pipeline, a set of electrodepairs lining the one or more flow tubes and in contact with a flowingmedia through the pipeline to generate and store power in concert withthe one or more permanent magnets, a plurality of downhole valvespowered by the MHD power generation system, and a processor connected tothe set of electrode pairs and the one or more permanent magnets, theprocessor executing a set of instructions on a non-transitory computerreadable media to calculate a water holdup measurement based upon anamount of power generated by the MHD power generation system.

According to an embodiment, the MHD power generation system isconfigured to calculate the water holdup based on fluid flow velocityand conductive fluid cut of the flowing media.

According to an embodiment, the plurality of downhole valves are chokedin order to decrease the fluid flow of a non-conductive fluid componentof the flowing media such that the fluid flow of conductive fluidcomponent of the flowing media in adjacent passages is optimized andmore power is generated.

According to an embodiment, a contact area between the flowing media,the set of electrode pairs, and the positioning of the one or morepermanent magnets, are each optimized.

According to an embodiment, the one or more permanent magnets and set ofelectrode pairs are arranged in a flow tube design using densityvariations to optimize the chance of capturing the continuous phase of aconductive fluid component of the flowing media.

According to an embodiment, the MHD power generation system is designedwith materials such that it can withstand high temperatures withoutdegradation.

According to an embodiment, there is provided a method for generatingand storing energy using the MHD principle, the method comprising thesteps of: flowing media through a MHD power generation system configuredin a pipeline; generating power using the MHD principle with a powergeneration system including one or more permanent magnets, a set ofelectrode pairs, and isolation material configured in concert with themedia flow, wherein the media flows through a set of pipes containingthe one or more permanent magnets, the set of electrode pairs, and theisolation material; storing the power so that it can be used downhole topower a set of electric valves simultaneously; controlling the flow ofthe media using one or more electric valves; and calculating the waterholdup based on the amount of power stored and generated.

According to an embodiment, the power generation system calculates thewater holdup based on the fluid flow velocity and conductive fluid cutof the flowing media.

According to an embodiment, the one or more electric valves of at leastsome flow passages are choked in order to decrease the fluid flow of anon-conductive fluid component of the flowing media such that the fluidflow of conductive fluid component of the flowing media in adjacentpassages is optimized and more power is generated.

According to an embodiment, the one or more permanent magnets and theset of electrode pairs are arranged in a flow tube design using densityvariations to optimize the chance of capturing the continuous phase of aconductive fluid component of the flowing media.

According to an embodiment, a contact area between the flowing media,the set of electrode pairs, and the positioning of the one or morepermanent magnets, are each optimized.

According to an embodiment, the MHD power generation system is designedwith materials such that it can withstand high temperatures withoutdegradation.

According to an embodiment, there is provided a MHD power generationsystem comprising: one or more permanent magnets, one or more flow tubesarranged inside the pipeline, a set of electrode pairs configured to bein contact with the outer surface of conductive flow tubes that are incontact with a flowing media through the pipeline to generate and storepower in concert with the one or more permanent magnets, a plurality ofdownhole valves powered by the MHD power generation system, and aprocessor connected to the set of electrode pairs and the one or morepermanent magnets, the processor executing a set of instructions on anon-transitory computer readable media to calculate a water holdupmeasurement based upon an amount of power generated by the MEM powergeneration system.

BRIEF DESCRIPTION OF DRAWINGS

The foregoing aspects, features, and advantages of embodiments of thepresent disclosure will further be appreciated when considered withreference to the following description of embodiments and accompanyingdrawings. In describing various embodiments illustrated in the appendeddrawings, specific terminology will be used for the sake of clarity.However, the disclosure is not intended to be limited to the specificterms used, and it is to be understood that each specific term includesequivalents that operate in a similar manner to accomplish a similarpurpose.

FIG. 1 illustrates a side perspective view of a general pipeline systemconfigured in accordance with an embodiment.

FIG. 2 illustrates a side perspective view of a general pipeline systemconfigured in accordance with an embodiment wherein a magnet isconfigured in the central section of a pipeline.

FIG. 3 illustrates a cross sectional view of a general pipeline systemconfigured in accordance to an embodiment wherein a magnet is configuredin the central section of a pipeline as similarly shown with respect toFIG. 2 .

DETAILED DESCRIPTION

Advantages and features of the systems and methods of accomplishing thesame will be apparent by referring to embodiments described below indetail in connection with the accompanying drawings. However, thesystems and methods are not limited to the embodiments disclosed belowand may be implemented in various different forms. The embodiments areprovided only for completing the disclosure and for fully representingthe scope of the disclosed technology to those skilled in the art.

For simplicity and clarity of illustration, the drawing figuresillustrate the general manner of construction, and descriptions anddetails of well-known features and techniques may be omitted to avoidunnecessarily obscuring the discussion of the described embodiments ofthe invention. Additionally, elements in the drawing figures are notnecessarily drawn to scale. For example, the dimensions of some of theelements in the figures may be exaggerated relative to other elements tohelp improve understanding of the various embodiments. Like referencenumerals refer to like elements throughout the specification.

Hereinafter, various embodiments will be described in detail withreference to the accompanying drawings.

Embodiments relate to a MHD power harvesting system with four maincomponents: permanent magnets, electrodes, isolation material, and aconductive flowing media. Varying setups between the magnets and theelectrodes can be designed, depending on type, length, size,orientation, and location of the pipeline system. As the multiphasemedia enters the pipeline and the MHD system, which is attached to aportion of the pipeline, the conductive liquid produces an outputvoltage when it passes through the magnetic field created by themagnets, which are oriented perpendicular to the flow of the media andelectrodes which are orthogonal to the flow of the media and themagnets. For example, in an embodiment, the magnets can be configured oneach side of a pipe, at 0 degrees and 180 degrees. In this embodiment,the electrodes can further be configured at 90 degrees and 270 degrees.In alternate embodiments, variations of this configuration can also beachieved such that at least some portions of the magnets are on opposingportions of a pipe and at least some portions of the electrodes are alsoon opposing portions of a given pipe. The current (I) generated by theconductive flowing media will be affected by the magnetic fieldstrength, the flow velocity, the conductive fluid mass volume, thecontact area of the electric conductor, the fluid density and thediameter of the pipeline. In general, for a particular configuration ofthe system, the stronger the magnetic field the more energy is produced,and the higher the fluid velocity the more energy is produced. Further,the more conductive the fluid in the system, the more energy may beproduced. In an embodiment, longer electrode sections and/or strongermagnetic field sections can be configured to achieve the desired energyoutput for a particular system. The rate of fluid flow can also be takeninto account when determining the configuration of a particular system.Additionally, the expected conductivity of the flowing media for aparticular system can also help determine the configuration parameters,such as magnet strength, and electrode size and length. However, theseare all static factors except for the flow velocity and conductivity.

In an embodiment, it may be desirable to split the overall flow intosmaller pipes and/or tubulars to better accommodate for sudden pressuredrops and/or pressure spikes. By spreading the flow out among manypipes, the overall effect of a pressure spike can be limited or at leastreduced.

It is generally known that according to Faraday's law of electromagneticinduction, any change in the magnetic field with time induces anelectric field perpendicular to the changing magnetic field given by theequation:

${E = {{- \frac{d\left( {BA} \right)}{dt}} = {- \frac{d\Phi}{dt}}}},$where E is the voltage or potential difference generated due to theinduced current, B is the magnetic field strength, A is the crosssection area, Φ is the magnetic flux. The negative sign in the equationabove indicates that the induced current will create another magneticfield opposing to the buildup of the magnetic field in the coil based onLenz's Law. When a voltage is generated by a change in magnetic fluxaccording to Faraday's Law, the polarity of the induced voltage is suchthat it produces a current whose magnetic field opposes the change whichproduces it. The induced magnetic field inside any loop of wire alwaysacts to keep the magnetic flux in the loop constant. If the flux isincreasing, the induced field acts in opposition to it. If it isdecreasing, the induced field acts in the direction of the applied fieldto oppose the change.

Since the magnetic field B is fixed for a permanent magnet, the equationbecomes:

${E = {{{- B}\frac{dl}{dt}D} = {{- B}vD}}},$where v is the flow velocity and D is the distance between twoelectrodes. The potential difference E can then be transferred to powervalves and the like. In an embodiment, the electrodes are in directcontact with the conductive material as it flows through the pipe. In analternative embodiment the electrodes can also be separated from theconductive material if the pipe section is made of a material that isconductive. To avoid corrosion of the electrodes, special considerationscan be made in a given configuration to shield them from corrosivematerials.

Generating and Storing Energy Using the Magnetohydrodynamic Principle

Using the magnetohydrodynamic (“MHD”) principle to generate power is awell-known concept in the field of power generation. Embodiments of thepresent invention optimize the fluid contact with the electrodes for lowwater cut wells and higher water cut wells to generate the most energypossible. A computer system tracks the amount of power generated andmakes a water holdup determination using this data.

There is an induced electromagnetic force from the flow of the media inthe present invention. The induced electric field density is given bythe equation E=vB, where v is the velocity of the media and B is themagnetic induction field generated by the magnets and electrodes

$I = \frac{U}{{R1} + {R2}}$is the current generated between the electrodes shown in FIG. 1 . Thereis a device connected to the electrodes with a resistance R2 and theresistance between electrodes R1 that is used to calculate the currentflow. Further, U is the velocity of the liquid multiplied by theelectric field strength generated by the magnets multiplied by thedistance between the electrodes. For reference, the general powerequations for a Faraday segmented MHD generator are as follows:Power={right arrow over (E)}×{right arrow over (J)}{right arrow over (J)}={right arrow over (J)}_(x)+{right arrow over(J)}_(y)+{right arrow over (J)}_(z), {right arrow over (J)}_(x)=0,{right arrow over (J)}_(y)=0J _(y)=σ₀ ·U·B·(1−K){right arrow over (E)}={right arrow over (E _(x))}+{right arrow over (E_(y))}+{right arrow over (E _(z))}, {right arrow over (E _(z))}=0E _(x) =−β·U·B·(1−K)E _(y) =U·B·(1−K)Where

-   -   E=Electric field in x, y and z direction    -   J=Faraday current in x, y and z direction    -   β=How many electrons move before next collision    -   K=Load factor (difference between closed and open circuit        voltage)    -   U=Fluid velocity    -   B=Magnetic flux density    -   σ₀=Conductivity        Such that        Power=K·U ² ·B ²·σ₀·(1−K)        To further illustrate this equation, an example calculation is        as follows. Assuming, for example, a flow channel being 3″        (76.2 mm) with 5 electrode pair segments in the flow direction.        There is a magnetic field (B) perpendicular to the electrodes (E        field) and electrode cross section is approximately 50 mm×10 mm.        With the permanent magnet we should be able to produce 0.41        Tesla (Using NdFeB, grade N52 magnet with Br_(max) of 14,800        Gauss (1.48 Tesla) and surface field at 4176 Gauss (0.41 T). If        for this example, we assume 100% water cut, conductivity of 25        S/m, and a flow velocity of 2 m/s, the following calculation is        done as follows:        1) Conductivity Through the Fluid Channel:

$\sigma_{0} = {{\sigma\frac{A}{l}} = {{2{{5\left\lbrack \frac{S}{m} \right\rbrack} \cdot \frac{{0.0}{{50\lbrack m\rbrack} \cdot {0.01\lbrack m\rbrack}}}{{0.0}{762\lbrack m\rbrack}}}} = {{0.1}6{4\lbrack S\rbrack}}}}$Where σ is the specific conductance per unit volume of a homogenousmaterial. Solving the power equation by assuming the load factor K to be0.5:

${Power} = {{K \cdot U^{2} \cdot B^{2} \cdot \sigma_{0} \cdot \left( {1 - K} \right)} = {{0.5 \cdot {2\left\lbrack \frac{m}{s} \right\rbrack}^{2} \cdot {0.41\lbrack T\rbrack}^{2} \cdot {0.164\lbrack S\rbrack} \cdot \left( {1 - 0.5} \right)} = {{0.028\lbrack W\rbrack} = {28{mW}}}}}$Thus, for multiple sets of electrode pairs, more energy may begenerated. If we have for instance 1 electrode pair with 5 electrodes weshould be able to generate 0.14 W power. Additional factors that mayinfluence and vary the power output can include magnet strength, magnetsize, electrode size, magnet shape, electrode surface area, flowrate,cross sectional area, and conductivity.

FIG. 1 shows the MHD principle in use in a general pipeline systemaccording to an embodiment of the invention. The MHD power storage andgeneration system 100 includes electrodes 102 and magnets 104. In thisembodiment, magnets 104 are on the outside of the pipeline while theelectrodes 102 are inside the pipeline 108 and in direct contact withthe multiphase flow 106 through the pipeline. In other embodiments, theelectrodes 102 can be configured in the structure of the pipeline 108itself or outside of the pipeline 108 if the pipeline 108 material isconducted. Such a configuration may be desirable to avoid corrosion ofthe electrodes 102. The multiphase fluid flow 106 goes from left toright through the pipeline 108. As the multiphase flow 106 goes throughthe harvesting system, a current is generated which is used to createenergy inside a battery connected to the electrodes 102. The purpose ofthe energy harvesting device is to generate power to control a valve inan inflow control valve (“ICV”) installed downhole or at a remotelocation with no access to other means of power. The valve may requirepower when there is water breakthrough in a well bore and an operatorwants to operate the valve. This can occur if there is waterbreakthrough because it might be desirable to shut down or limit theamount of water from the water producing zone. The function of thedownhole valve is to choke the water-producing interval when observed inorder to regain hydrocarbon production. Before the water break-throughoccurs the valve will not require much power to operate. The more waterflowing through the harvesting area 110, which contains a pair ofelectrode sets 102, the more energy is generated and stored. This powerwill then be used to power a valve for instance to choke the zone ofinterest in order to increase pressure and hence reduce the water flow.

Water Holdup Determining Using the MHD Principle Downhole

The same device that is used for power generation can be used for waterholdup measurement. The amount of power generated is directly related tothe amount of water in the system. This linear relationship can be usedby the system to determine the water cut and water holdup measurement.Further, in an optimized embodiment of such a device, the contact areabetween the water and the electrodes, as well as the strength, size, andpositioning of the magnets can be optimized. The design includes flowtubes that are used to capture the least resistive path for theelectrodes and magnetic flux lines to flow to.

The flow tube design in FIG. 2 illustrates another embodiment. Thisconfiguration is highly efficient when water is the heaviest componentin the flowing media. This is because, in general, a higherconcentration of water is flowing through the lower parts in such aconfiguration. Correspondingly, the higher tubes, will most likelyexperience more oil, and hence produce less electricity. The flow tubesuse the density variations in the media to optimize the chance ofcapturing the continuous phase of conductive fluid best. Depending onthe Reynolds number of the media, usually water flows in the low end ofa horizontally placed pipe and gas is at the high end. The MHD system200 in FIG. 2 forces the higher density conductive phase 212 into thelower section 214 of the pipe 208 so the flow rate will increase andincrease the contact area for the power generation of the entire flowingmedia 206 through the whole pipe section 210 that is outfitted with theMHD system 200. The water 212 flows lower than the Oil 216 and gas 218.The electrodes 202 surround a magnet 204 through the whole system 200.The magnet 204 has flux lines perpendicular to the flow direction andthe electric field in order to generate power. In this example, thetotal power generated by the system 202 and transferred for storage isgiven by the following equation: TP=5*I²*R1=(U²*R1)/(R1+R2){circumflexover ( )}2 where the internal resistance R1 depends on the conductivityof the fluid.

FIG. 3 shows the cross sectional view of the flux lines in the MHDsystem 300 according to another embodiment of. A permanent magnetsuitable for the downhole environment can be used in the center of thepipe 308. Pairs of electrodes 302 are arranged outside the magnet 304and create flux lines 306 coming from the magnet 304. In an embodiment,the power is generated most optimally if the electrodes 302 areconfigured to be perpendicular to the magnetic field. This setup willalso have the effect of creating a pressure drop in the systemincreasing the kinetic energy and the power generation will alsoincrease. If the velocity of the liquid is known, then the amount ofpower generated will be directly related to the conductive fluid flow.The system 300 can be used at the surface for power generation for anydevice connected to the pipeline and so the system 300 will not needalternate power sources.

The singular forms “a,” “an,” and “the” include plural referents, unlessthe context clearly dictates otherwise.

The foregoing disclosure and description of the disclosure isillustrative and explanatory of the embodiments of the disclosure.Various changes in the details of the illustrated embodiments can bemade within the scope of the appended claims without departing from thetrue spirit of the disclosure. The embodiments of the present disclosureshould only be limited by the following claims and their legalequivalents.

The invention claimed is:
 1. A magnetohydrodynamic power generationsystem comprising: a permanent magnet coupled with a pipeline; elongateelectrodes mounted lengthwise within the pipeline at spaced apartlocations, the locations being in a path of a fluid that selectivelyflows through the pipeline, and the locations being intersected by amagnetic field generated by the magnet, so that when the fluid flowsthrough the pipeline and across the electrodes, an electrical current isgenerated between the electrodes; and a downhole valve in electricalcommunication with the electrodes and that selectively receives theelectrical current.
 2. The magnetohydrodynamic power generation systemof claim 1, wherein the permanent magnet is mounted on an outer surfaceof the pipeline and comprises a first permanent magnet, the systemcomprising a second permanent magnet that is mounted onto the outersurface of the pipeline on a side opposite the first permanent magnet,and wherein the electrodes comprise a pair of electrodes that aremounted opposite one another along an inner surface of the pipeline andorthogonal to the first and second permanent magnets.
 3. Themagnetohydrodynamic power generation system of claim 1, furthercomprising elongate flow tubes disposed lengthwise within the pipelineand wherein the permanent magnet is elongate and cylindrical anddisposed in a middle portion of the pipeline and surrounded by the flowtubes, and wherein a pair of electrodes is mounted within innersidewalls of each of the flow tubes and spaced opposite from oneanother.
 4. The magnetohydrodynamic power generation system of claim 1,further comprising a processor in communication with the electrodes andthe valves, the processor the processor executing a set of instructionson a non-transitory computer readable media to calculate a water holdupmeasurement based upon an amount of power generated by themagnetohydrodynamic power generation system.
 5. The magnetohydrodynamicpower generation system of claim 1, wherein the electrodes are mountedon inner sidewalls of the pipeline and contoured complementary to aninner surface of the pipeline.